Hoe excavator



Feb. 21, 1950 L. o. MCLEAN 2,498,000

HOE EXCAVATOR Filed May 7, 1948 2 Sheets-Sheet l IN V EN TOR.

Lean/v0 0. M lsn/v BY 0ansovi HIS ATTORNEY Feb. 21, 1950 L-. O. MCLEAN 2,498,000

HOE EXCAVATOR Filed May '7, 1948 2 Sheets-Sheet? IN V EN TOR.

lam/v0 0. M ZEflN BY Al/d QTTOPA/EK Patented Feb. 21, 1950 UNITED STATES PATENT OFFICE HOE EXCAVATOR Leland O. McLean, Marion, Ohio Application May 7, 1948, Serial No. 25,631 Claims. (C1. 214 1ss) The invention relates generally to excavators of the back-hoe type, and more particularly to the mechanism for providing a new improved shoulder, elbow and wrist movement of the dipper by means of but two lines, a hoisting line and adrag- 5 line, wound upon two conventional winches powered and controlled independently from a common source of power, such as an internal combustion engine mounted on the cab of the excavator.

One of the objects in view is to provide improved means for tilting the dipper into the proper digging position before starting to haul it towards the cab, instead of merely moving the dipper into a raking position as is the case with the present excavators now in use. Thus the dipper is properly tilted into effective digging position, instead of only approximating such position as in the present practice.

Another object is to maintain the dipper in proper tilted position until it has completed its travel toward the cab.

Another object is to provide means for lowering the back end of the dipper when the digging action has been completed to retain the burden of dirt or soil until it has been swung into thedesired dumping radius.

Still another object of the invention is the provision of means for raising the back end of the dipper for dumping the load.

Another object is the provision of simple and effective means, easily controlled from the cab, for providing the proper tilting and moving the dipper in its operations during excavation work.

Other novel features of construction and arrangement of parts will appear from the following description.

In the accompanying drawings, wherein is illustrated a practical embodiment of the principles of the invention,

Fig. l is a side elevation illustrating the structure of the hoe excavator;

Fig. 2 is a plan view, with the dipper omitted, showing the method of reeving the hoist line on the sheaves mounted on the gantry and the dipper arm;

Fig. 3 is an elevation, on enlarged scale, of the dipper-arm and the dipper looking from the left in Fig. 1;

Fig. 4 is a sectional view of the dipper-arm taken along the dotted line 4-4 of Fig. 1;

Fig. 5 is a fragmentary plan view of the boom showing the arrangement of the sheaves for the dragline;

Fig. 6 is a fragmentary side elevation illustrating the relative positions of the boom and the 55 dipper as the latter is lowered into engagement with the ground to be excavated.

Fig. 7 is a like view showing the relative positions of the boom and the dipper as the bottom of the latter is tilted toward a horizontal position as it sinks into the ground.

Fig. 8 is a like view showing the tilting of the dipper continued until the bottom of the same is in a substantially horizontal position to produce a flat bottom in the ditch or excavation being formed.

Fig. 9 is a like view showing the front of the dipper elevated to retain its contents and to prevent spilling the load while the dipper is being swung over a waiting truck or the spoil .pile;

Fig. 10 is a like view showing the dipper raised and reversed to dump its load.

Fig. 11 is a schematic view showing the reeving of the hoist-line on the gantry and dipper-arm.

Referring to the drawings, 20 indicates the cab of the excavator which, as is the common practice, is rotatably mounted on a vertical axis on the tractor andprovided with a motor for selectively driving the tractor, swinging the cab and operating the boom and the dipper. 2| indicates the gantry or mast, 22 the boom, 23 the dipperarm, and the dipper.

The gantry may be of the usual type comprising a pair of legs converging toward their upper extremities and pivoted to the cab at theirlower ends on a horizontal axis so that their forward inclination relative to the cab may be varied as required for the particular work to be done.

25 indicates a winch mounted in the cab and connected with power transmission means for se lective rotation in either direction or for looking it stationary. 26 indicates the gantry guy line which has a portion wound on the winch 25 and which extends vertically and is led over the pulley 21 journaled on a horizontal axis in the bracket 28 which may be mounted in the upper portion of the cab.

The guy line 26 is led forward over the pulley 21 and is passed down over a pulley 29 mounted on the top of the gantry 2 l. The guy line thence extends rearwardly and around the twin pulleys 30 journaled on vertical axes on the bracket 28, and thence forwardly and up around the guy line pulley 3! on the gantry, and thence rearwardly to the bracket 28 where it is dead-ended at 32.

Thus by either winding up the guy line on the winch 25 or causing it to unwind therefrom,

the angularity of the gantry may be adjusted at will.

33 indicates a transversely disposed axle extending between the legs of the gantry adjacent the upper end of the latter. The guy line pulleys 29 and SI are journaled on the axle adjacent either end of the latter and between the legs of the gantry, and between said pulleys three pulleys 3 3, 35 and 35 are journaled on said axle to receive the hoist line.

The boom 22 is pivotally attached to the cab on the same horizontal axis as is the gantry 2i, and the dipper-arm 23 is pivotally attached to the free end of the boom on a horizontal axis at a point adjacent the upper end of the dipper-arm but spaced therefrom. The dipper-arm, as illustrated in Fig. 4, is preferably of rectangular hollow cross-sectional form and for a short distance from its upper end the front and rear walls of the arm are omitted to provide clearance for the intermediate one of three hoist line pulleys 3T, 38 and 39 which are rotatably mounted on an axle All extending transversely of the dipper-arm and beyond the same at either side, the intermediate pulley 38 being mounted on the axle between the side walls of the dipper-arm and the pulleys 31 and 39 being mounted on the protruding portions of the axle.

The dipper 24 is shown as of the conventional type with an open front provided with digging teeth substantially vertical sides and a bottom merging by means of a curvature into the back wall of the dipper.

The angular diverging arms M are secured as by bolts to either side of the dipper-arm 23 adjacent its lower end and the lower extremities of the said arms are provided with aligned journals 42 which register from without with similar journals provided in the top of the side walls of the dipper at the front thereof, and pivot bolts 43 are inserted through the openings of said registering journals to pivotally attach the dipper 24 at its top front to the lower end of the dipperarm 23.

44 indicates a guide bar extending longitudinally of the front face of the dipper-arm 23 and fixedly-mounted thereon by any convenient means, such as the spaced eye-brackets 45 which hold the bar 44 in spaced relation with the surface of the dipper-arm, and also prevent longitudinal movement of the bar relative to the dipper-arm.

46 indicates a crosshead provided with a vertical hole Al through which the guide bar extends. The rear surface of the crosshead has a sliding fit with the front wall of the dipper-arm so that the crosshead is slidable on the bar 44 between the brackets 45, and is maintained against lateral swaying relative to the dipper arm.

48 indicates a pair of links having their upper ends pivotally attached on the same horizontal axis to the opposite sides of the crosshead 45. Said link diverge downwardly and at their lower ends are pivotally attached to the upwardly extending lugs 49 at either side of the top rear of the dipper 24.

50 and Si indicate a pair of winches mounted in the cab and preferably 'side-by-side. Each of the winches is provided with independent means for power-rotating the winch and for locking it stationary.

The winch D has wound around it one end portion of the hoist line 52, while the winch 5! has wound about it one end portion of the dragline 53.

The hoist line 52 extends from the winch 55 up over the gantry pulley 3 5; thence extending forwardly and over and down around the dipperarm pulley 31 as illustrated at 52a; thence extending rearwardly, as illustrated at 52b, to the gantry pulley 36 and down around the same; thence as illustrated at 52c, extending forwardly to the dipper-arm pulley 39 and up around the same; thence rearwardly as illustrated at 52d to the central gantry pulley 35 and up around the same, thence extending forwardly, as illustrated at Me, to the central dipper-arm pulley 33 and down around the same; and the free end of the hoist line is secured in the rope socket 554 pivoted to the top of the crosshead, whereby the latter is suspended from the hoist line 52. To prevent the hoist line from accidental disengagement from the pulley 38 a small guard pulley is mounted on swinging side plates 55 pivotally mounted on the axle 33.

The dragline 53 extends forward from the winch 5| and between coacting guide pulleys 5'! and 58 mounted on one side of the boom 22, and thence extends around a floating pulley 53, which is rotatably mounted in the block 6% and rotates on a vertical axis. The return flight of the dragline extends to and is passed around a third pulley 6| mounted on the opposite side of the boom 22 from the pulleys 51 and 58 and is dead-ended on the boom at 63.

The pulley block 60 is connected to the front of the side walls of the dipper 24 by the diverging chains 62 at a point materially spaced below the connections between the arms M to the dipper, preferably at about one-half of the distance between the bottom of the dipper and the dipper-arm connection thereto.

In Fig. l the tension on the dragline 55 has been reduced, by partially releasing the brake on winch 5|, and the weight of the boom, dipper-arm and dipper is imposed on the hoist line 52, causing the crosshead 46 to slide upwardly along the dipper-arm, lifting the dipper as the boom is lowered toward the ground by feeding out the hoist line.

In Fig. 6 the tension on the dragline has been released by releasing the brake on winch 5| while the hoist line 52 is held by the brake on winch 55 with the weight of the boom, dipperarm and dipper imposed on the hoist line 52 causing the dipper to assume automatically the position to be lowered to the ground by feeding out the hoist line to start digging.

In Fig. '7 the toothed edge of the dipper has started the digging action by the counter-clockwise revolving action about the pivot 33 and the pull on the dragline 53 plus the weight of the boom and dipper-arm imposed at pivot point 43 caused by releasing the tension on the hoist line 52.

In Fig. 8 the dipper has continued its digging action, the bottom having assumed a horizontal position so as to form a horizontal bottom level in the ditch of excavation, caused by pulling on dragline and varying the tension on the hoistline to raise or lower the back end of the bucket as desired.

In Fig. 9 tension on the dragline has elevated the front of the dipper to retain the load against spilling while the dipper is raised to be swung into dumping position by the rotation of the cab.

In Fig. 10 the boom is still further raised by a pull on the hoist line and slacking off the dragline, thus causing the dipper to be inverted and dump its contents.

Again, the use of a rigid link member pivotally connected to the crosshead and the rear of the d pper; provides improved control of the swing of the, dipper on its pivotal connection withthe dipper-arm. The use of twin connecting links also prevents side sway of the dipper and thus its-., application to the work is accurate so that, for instance, a ditch or trench having vertical walls and uniform bottom may be dug quickly and uniformly.

The principle of the performance of the hoe assembly is ,that the force of a four part line can be applied to the upper end of the'dipperarm, the force of the one part line to the crosshead and the force of a two part line to the dipper bail below the pivot point 43. The different leverages are involved in its functions and the fact that the weight of the boom and the dipper-arm including the inherent tendency to push "the pivot point 43 away from the machine can be applied in varying proportions, to the pivot point, assist the dragline when pulled, to revolve the bucket counter-clockwise about the pivot 43 the desired amount.

The multiple reeving of the hoist line on and between the sheaves mounted on the gantry and the sheaves mounted on the dipper-arm, the single end of the hoist line over a sheave-mounted on the dipper-arm and dead-ended to the crosshead 46 and the two part reeving of the dragline on and between the sheaves mounted on the side of the boom and the sheave 59 in the block 60 in combination with the various leverages, making it possible to obtain three actions with only two lines on a standard two actuated drum machine, provide a novel and very substantialadvanoe in hoe-excavator art.

I. '.claim: w

1; In .a hoe-excavator, the combination with a support, of a'gantry mounted on the support, a boom pivotally mounted on the support, a dipper arm pivotally attached intermediate of its ends on the boom, a dipper pivotally attached adjacent the top of its open front to the lower end of the dipper-arm, a plurality of sheaves mounted in equal number on the upper ends of the gantry and the dipper-arm, a pair of winches, a hoist line having one end woundaround one of said winches and having its intermediate portion multiple reeved between the sheaves on the gantry and the dipper-arm and having its other end connected to the dipper at the rear of the latter, and a dragline connected to the open front of the dipper below the attachment of the latter to the dipper-arm and having an end portion wound about the second winch.

2. The structure of claim 1 characterized by the connection between the end of the hoist line and the dipper being in the form of a member mounted to slide longitudinally of the dipperarm, and link means pivotally attached at its upper extremity to the member and at its lower extremity to the dipper.

3. The structure of claim 1 characterized by the connection between the end of the hoist line and the dipper being in the form of a crosshead on the support, a boom pivotally mounted on the support, a dipper arm pivotally mounted intermediate of its ends on the boom, a dipper pivotally attached to the lower end of the dipper arm,

'a plurality of sheaves mounted in equal number ontheupper ends of the gantry and 0f the dipper arm, a pair of winches, a hoist line having one end wound on one of the winches and having its intermediate portion multiple-reeved on the sheaves on the gantry and on the dipper arm and having its other end connected to the rear of the dipper, and a dragline connected to the dipper below the pivot point of the latter and having an end portion wound on the second winch.

5. A two-line hoe excavator comprising in combination with a support, of a gantry mounted on the support, a boom pivotally mounted on the support, a dipper arm pivotally mounted intermediate of its ends on the boom, a dipper pivotally attached on an axis adjacent the top of its open front to the lower end of the dipper arm, a plurality of sheaves mounted in equal number on the upper ends of the gantry and of the dipper arm, a pair of winches, a hoist line having one end wound on one of the winches and having it intermediate portion multiplereeved on sheaves on the gantry and on the dipper arm and having its other end attached to the dipper at the rear thereof, and a dragline connected to the front of the dipper below the pivot point of the latter and having an end portion wound on the second winch.

, LELAND O. McLEAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,823,662 Orlofi Sept. 15, 1931 1,840,550 Wilson Jan. 12, 1932 2,000,150 Siebert May '7, 1935 2,191,569 Kuhsel Feb. 2'7, 1940 2,303,852 Linn Dec. 1, 1942 FOREIGN PATENTS Number Country Date 306,260 Great Britain Feb. 21, 1929 

